The head of the UK government’s infrastructure advisory body has warned regulator Ofcom to tackle “deplorable” mobile phone coverage in a letter to CEO Sharon White.

Lord Adonis, who chairs the National Infrastructure Commission (NIC), wrote to White following the publication of Ofcom’s annual report on the UK’s communications infrastructure, urging the watchdog to consider major changes in order to boost connectivity across the country.

Ofcom’s recent Connected Nations 2017 report found mobile coverage across the UK is around 10 percentage points lower than previously claimed, with 30% of the country not receiving coverage good enough for calls and texts from all four mobile operators.

“Despite licence obligations that were intended to provide coverage to 90% of the UK's landmass by the end of 2017, large parts of the country remain without reliable coverage – with almost a third of the UK’s geography unable to receive a signal from all four operators,” Adonis wrote.

“Given the seriousness and scale of gaps in the UK’s mobile coverage, I believe Ofcom should urgently propose an action plan to government for radically improving mobile coverage in the short to medium term.”

Ofcom changed its definition on what counts as “good mobile coverage”, with the hange showing geographic landmass coverage where a user can make an uninterrupted mobile phone call for at least 90 seconds. The regulator’s report found coverage could be 10 percentage point lower than under old measurement.

He urged Ofcom to “put all possible options on the table” including regulatory changes, mast-sharing, national roaming, and freeing up additional spectrum.

“I believe it is now crucial that all options are considered to radically improve mobile coverage across the UK and ensure that consumers receive the service they pay for and deserve.

“With mobile telecommunications now firmly established at the heart of modern society and the economy, and ubiquitous access to mobile networks increasingly viewed by consumers as a basic right, a step change in mobile coverage is required. I trust you will consider the above suggestions as you look to use the full force of Ofcom’s powers to improve the current situation.”